From what I can tell, this is what happened:User A has a local replica of their mail.
User A decides to set up archiving and tell Notes to use their local mail replica as the archive database.
The Mail file now has the archive database look: In the upper-left corner it says Mail Archive instead of Mail. The toolbars have little filing cabinets as their background image, etc.
How do I undo this? Replacing the design doesn’t change anything. I’m guessing there’s a profile document with a flag set somewhere, but where is it and how do I change it.